Creating ARM Executable and Linkable Format Files

With the GNU ARM Toolchain installed, enter the following two lines in the terminal.


arm-elf-as --gdwarf2 -mcpu=arm7tdmi -o FILENAME.o FILENAME.s 
arm-elf-ld -o FILENAME.elf FILENAME.o


Where FILENAME.s is the name of your ARM assembly code file.

A few quick notes: the parameter 'gdwarf2' is used to maintain debugging information inside the file. It will come in handy when using arm-elf-gdb. The mcpu parameter tells the assembler what architecture the file is to be targeted towards.

Alternatively, copy the following code (EDIT: and replace the three indents on lines 21, 24, and 28 with tabs!), and save it as 'makefile' in the same directory as the .s file. Anytime you need to create an ELF file using filename.s, simply type 'make filename.elf'.

Download makefile

#
# Makefile for ARM Projects
# Author: S Hodgson
# Date: July 2011
#
# Usage: make filename.elf
#   i.e. if helloworld.s is the ARM assembly code,
#        execute 'make helloworld.elf'
#

# Linker and Assembler
LD      = arm-elf-ld
AS      = arm-elf-as

# Flags
DBGFLAG = --gdwarf2
ARCH    = -mcpu=arm7tdmi

# Create Files
%.elf : %.o
    $(LD) -o $@ $^

%.o : %.s
    $(AS) $(DBGFLAG) $(ARCH) -o $@ $^

# Clean - Warning: Removes ALL object and elf files
clean:
    rm -rf *.o *.elf



Edit: As Patrick pointed out, the indentation MUST be tabs, not spaces...